This study is designed to examine the chemical composition and antioxidant activity of the essential oil and different solvent extracts of Vitex agnus castus. GC and GC-MS analysis was resulted in the detection of 27 components, representing 94.5% of the oil. Major components of the oil were 1,8-cineole (24.98%), sabinene (13.45%), ot-pinene (10.60%), alpha-terpinyl acetate (6.66%), and (Z)-beta-farnesene (5.40%). Antioxidant activities of the samples were determined by three different test systems, DPPH, beta-carotene/linoleic acid and reducing power assays. In all systems, water extract exhibited excellent activity potential than those of other extracts (hexane, dichloromethane, ethyl acetate and methanol) and the oil. As expected, amount of total phenolics was very high in this extract (112.46 +/- 1.22 mu g GAEs/mg extract). Dichloromethane extract has been found to be rich in flavonoids. A positive correlation was observed between the antioxidant activity potential and total phenolic and flavonoid levels of the extracts. (C) 2009 Elsevier Ltd. All rights reserved.